1.
day and night, constantly, always
Continuously without rest; working or occurring both day and night.
研究者たちは日夜努力している。
The researchers are working hard day and night.
日夜訓練を続けている。
They continue training day and night.
工場は日夜稼働している。
The factory operates around the clock.
COMPOUND: 日 (day) + 夜 (night)
REGISTER: Somewhat formal/literary. In casual speech, いつも or ずっと might be used instead.
SIMILAR EXPRESSIONS:
- 昼夜 (day and night)
- 四六時中 (around the clock, constantly)
- いつも (always)
- 絶えず (constantly, unceasingly)
TYPICAL USAGE: Often used with verbs indicating effort, work, or continuous activity.